Air-tube for pneumatic tires.



I. B, JEFFRIES.

AIR TUBE FOR PNEUMATIC TIRES.

APPLICATION men AUG.2!,19H.

1 ,285,'7 l 9 Patented Nov. 26, 1918.

AIR-TUBE FOR PNEUMATIC TIRES.

Specification of Letters Patent.

Application filed August 21, 1917. Serial No. 187,408.

To all no ham it may concern Be it known that LIsAAc BENJAMIN J EFF- RIES, known and trading as lsAAo BENJA- MIX, a subj ect of the King of Great Britain, residing at Llanelly, in the county of Carniarthen, South Wales, have invented certain new and useful Improyements in Air- Tubes for Pneumatic Tires, of which the following is a full, clear, and exact description.

The object of the present invention is to construct an improved self-sealing air tube for pneumatic tires. 7

The present invention relates to that type of air tube in which a number of strips of thin rubber are cemented or vulcanized to the tube along one edge only, leaving the greater portion of the strips loose and in contact with the inner surface of the tube or adjacent thereto. strips are arranged transversely, and in other cases longitudinally, of the tread. Such strips are so fixed that each strip overlaps the next strip and acts as a flap valve when the tube is punctured. It has also been proposed to fix a number'of separate small iiaps in rows slightly separated across the inside of the air tube, like iish scales, but such a construction entails considerable work.

According to the present invention 1 employ iong strips. and each strip is cut from its loose edges toward that edge which is fixed to the air tube. so thav each long strip is formed into a number of short flaps. the sides of which are in close contact. This method of manufacture effects a considerable saving or". time compared with the iixing of separate flaps, and produces a better article than the use of strips which have an uncut loose edge. The cuts are so arranged that those in an under strip of rubber pass under the centers oi the iiaps above them. The strips are preferably of such width that there are at least two layers of the protecting iiaps over the Whole of that portion oi! the air tube which it is desired to protect. Th strips and flaps. and any portion of the air tube between the strips, may be coated with a suitabie nonahying material, such as glycerin or soft soap. This non-drying materi'l will assist in making an air-tight joint between the iiaps and the inner tube when a puncture takes place.

It will he understood that the strips may be fixed in position on the air tube when this latter has been turned inside out. The

In some cases thesethat the uncut edge 5 tube is then returned and the ends of the tube will be connected in any usual manner. The strips may, however, be fixed in position upon the material from which the tube is to be made, which material is then put onto a mandrel or former and closed along its inner side in an" usual manner.

The invention is illustrated in the accompanying drawings, in which Figure 1 is a section of a portion of an air tube showing the interior surface of the outer half of the tube, and Fig. 2 is a similar view showing a modification.

Figs. 3 and 4 show face views of two forms of the strips to be applied to the air tube.

Fig. 5 is a longitudinal section of part of the air tube shown in Fig. 1, taken on the line 55, and Fig. 6 is a transverse section of part of the tube shown in Fig. 2, taken on the line 6-6.

Fig. 7 is a transverse section of an air tube showing a further modification. This view is diagrammatic so far as the strips and flaps are concerned.

Fig. 8 is a face view of a strip and Fig. 9 is a 12168 view of a modified form of strip.

in Figs. 1, 2. 5 and 6, the air tube a is oi any ordinary kind, being made entirely from a sheet oi rubber, and in the interior thereof are cemented or vuicanized long strips 5 of thin rubber, which are cut at b to form separate flaps f, the sides of which are in close conta t. These strips 5 are-fixed to the air tube a aiong their uncut sides 6 ieaving the flaps b loose in the interior of the air tube and as close to ti body of the tube a as possible. The flaps L are of such a length that there are at least two layers at every part of the air tube which is likely to be punctured.

in l the strips 5 are shown fixed train JQl) across ihc inner surface of the tube a, but it is preferred to'fix the strips 5 lougitudiualiy oi? the air tube as shown. in 2. as a tube thus constructed is more easily joined up at the ends without leaving a space huvii f no flaps E or where the flaps 5 do not properly overlap each other.

' The strips I), when out at T as shown in without removing any portion thereof, and fixed within the air tube (a trans- 'y thereof as shown in Fig. 1, have a tendency for the edges 71 of the flaps to overlap adjacent flaps b of the same strip, as shown in 8. This is due to the fact of the strip, being Patented s... cc. nus

fined to the air tube a When this latter is in side out, compressed when the tube returned, Whereas the outer edges of the flaps Z2 retain their original length. This lateral overlapping or the strips 5 should be avoided the best results are obtained when all the flaps just meet at the ed -es as shown in. Fig. ii.

In order to obtain. the desired result, the strips b may be slightly cut away at 71 shown in Fig. 3 so that their bases Wider than their outer ends, or the strip shown in Fig. 4 may be stretched longitudinally until it assumes the appearance shown in Fig. 3, and it may be attached to the air tube a in this stretched condition.

When the strips are attached lougitudinaily to the air tube a, as shown in Fig. 2 the flaps have little or no tendency to over lap each other at the outer edges if, as shown in Fig. 8.

It may happen thatatire becomes entirely or partially deflated owing to a leaky valve in Which case a nail passing through the outer cover would probably puncture the air tube on the rim side thereof. To avoid this inconvenience the air tube a may be provided Witha self-sealing compoundcloca'ted within the body thereof as shown in Fig. 7. This self-sealing compound may be located on both sides of the tube as shown in Fig. l,

as is Well known in the art.

Although the strips 7) shown straight 111 Figs. 1, :2, 3, 4 and they may be arcnate when arranged transversely of the tube. A portion of such a strip is shown in Fig. 9.

It Will be understood that the Width of the strips 7) may be varied and that the cuts 12 may be made at Various distances apart. In Fig. 9 the Width of the strips 6 is less, and the cuts 12 are Wider apart than shown in 3, 4 and 8.

in Figs. 5 and 6 (Z represents the non-dryin material such as glycerin or softsoap.

What I claim as my invention is 1. In. an air tube for a pneumatic tire, the combination of a tube, long strips fixed at one edge to the interior of said tube and overlapping each other, and flaps formed in the loose edges of said long strips by cutting these latter, the said flaps being Wider at their bases than at their outer ends when the -long strips are fixed to the tube inside out and the edges of such flaps just meeting when the tube is returned, substantially as set forth.

In an air tube for a pneumatic tire, the

combination of a tube, long strips fixed at one edge to the interior of said tube and overlapping each other, and flaps which are wider at their bases than at their outer ends when the long strips are fixed to the tube when it is turned inside out, said flaps being produced by cutting away portions of the loose strips, substantially as set forth.

In witness whereof I have hereunto set my hand.

.iSAAC BENJAMIN JEFFRIES. 

